Display device

ABSTRACT

A display device includes: a substrate including a display area at which an image is displayed with light, a non-display area which is adjacent to the display area, and a groove in the substrate, in the non-display area thereof; a light emitting element which generates and emits the light, disposed on the substrate in the display area thereof; and a common voltage transmitting line through which a common voltage is transmitted to the display area, disposed on the substrate in the non-display area thereof. The substrate further includes in each of the display area and non-display area thereof: a first insulating film, and a second insulating film disposed on the first insulating film. The groove extends into the second insulating film in a direction toward the first insulating film.

This application claims priority to Korean Patent Application No.10-2017-0116836 filed on Sep. 12, 2017, and all the benefits accruingtherefrom under 35 U.S.C. § 119, the entire contents of which areincorporated herein by reference.

BACKGROUND (a) Field

The present disclosure relates to a display device, and in detail,relates to a display device in which contact resistance of a commonvoltage transmitting line is reduced without extending a width of aperiphery portion to which a common voltage is transmitted through thecommon voltage transmitting line.

(b) Description of the Related Art

A display device includes a liquid crystal display (“LCD”), a plasmadisplay panel (“PDP”), an organic light emitting diode display (“OLED”),a field effect display (“FED”), an electrophoretic display, etc.

The organic light emitting diode display includes two electrodes and anorganic emission layer interposed therebetween. Electrons injected froma cathode that is one of the two electrodes and holes injected from ananode that is the other of the two electrodes are bonded to each otherin the organic emission layer to form excitons, and light is emittedwhile the excitons discharge energy.

In the organic light emitting diode display, each unit pixel includesswitching elements such as a switching thin film transistor and adriving thin film transistor, a capacitor and an organic light emittingdiode. A driving voltage is provided to the driving thin film transistorand the capacitor from a driving voltage line, and the driving thin filmtransistor serves to control an electrical current flowing to theorganic light emitting diode through the driving voltage line. Also, acommon voltage line connected to the common electrode as a cathodeprovides a common voltage to the cathode such that a potentialdifference is formed to the common electrode and the pixel electrode asan anode, such that electrical current flows.

The common voltage is transmitted to the common electrode throughcontact between the common electrode and a common voltage transmittingline of a contact area disposed at a periphery portion of the organiclight emitting diode display.

SUMMARY

Exemplary embodiments provide a display device reducing the contactresistance of the common voltage transmitting line without extending theplanar width of the non-display area around the display area of thedisplay device.

A display device according to an exemplary embodiment includes: asubstrate including a display area at which an image is displayed withlight, a non-display area which is adjacent to the display area, and agroove in the substrate, in the non-display area thereof; a lightemitting element which generates and emits the light, disposed on thesubstrate in the display area thereof; and a common voltage transmittingline through which a common voltage is transmitted to the display area,disposed on the substrate in the non-display area thereof. The substratefurther includes in each of the display area and non-display areathereof: a first insulating film, and a second insulating film disposedon the first insulating film. The groove extends into the secondinsulating film in a direction toward the first insulating film.

The common voltage transmitting line may overlap the groove.

The light emitting element may include an electrode layer, and theelectrode layer may be in contact with the common voltage transmittingline at a position overlapping the groove.

The groove of the substrate may extend only into the second insulatingfilm.

The substrate may further include a first barrier film disposed betweenthe first insulating film and the second insulating film, and the groovemay penetrate the second insulating film and extend into the firstbarrier film.

The groove of the substrate may penetrate the second insulating film andmay extend into the first insulating film.

The groove may be formed in plural.

A display device according to an exemplary embodiment includes: asubstrate including a first insulating film; a second insulating filmdisposed on the first insulating film; and a groove extended into thesecond insulating film in a direction toward the first insulating film;a pixel at which an image is displayed; and a common voltagetransmitting line through which a common voltage is transmitted to thepixel, disposed on the substrate. The common voltage transmitting lineoverlaps the groove formed in the substrate, and the common voltagetransmitting line is connected to the pixel at a position overlappingthe groove.

According to one or more of the exemplary embodiments, a surface contactarea between the common voltage transmitting line and the commonelectrode may be increased without extending the width of thenon-display area around the display unit of the display device, therebyreducing contact resistance of the common voltage transmitting line.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages and features of this disclosure willbecome more apparent by describing in further detail exemplaryembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a top plan view of an exemplary embodiment of a display deviceaccording to the invention.

FIG. 2 is a schematic cross-sectional view taken along line II-II ofFIG. 1.

FIG. 3 is an equivalent circuit diagram of an exemplary embodiment of apixel of a display device according to the invention.

FIG. 4 is an enlarged cross-sectional view of an exemplary embodiment ofa contact area of the display device of FIG. 2.

FIG. 5 is a cross-sectional view of another exemplary embodiment of acontact area of a display device according to the invention.

FIG. 6 is a cross-sectional view of still another exemplary embodimentof a contact area of a display device according to the invention.

FIG. 7 is a cross-sectional view of a contact area of a display deviceaccording to a comparative example.

FIG. 8 and FIG. 9 are electron micrographs showing exemplary embodimentsof a portion of a contact area of a display device according toexperimental examples.

FIG. 10 is a schematic cross-sectional view of another exemplaryembodiment of a display device according to the invention.

DETAILED DESCRIPTION

The invention will be described more fully hereinafter with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. As those skilled in the art would realize, thedescribed embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the invention.

The drawings and description are to be regarded as illustrative innature and not restrictive. Like reference numerals designate likeelements throughout the specification.

Further, in the drawings, a size and thickness of each element arearbitrarily represented for better understanding and ease ofdescription, and the present invention is not limited thereto. In thedrawings, the thickness of layers, films, panels, regions, etc., areexaggerated for clarity. In the drawings, the thickness of layers,films, panels, regions, etc., are exaggerated for the convenience ofdescription.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being related to another elementsuch as being “on” another element, it can be directly on the otherelement or intervening elements may also be present. In contrast, whenan element is referred to as being related to another element such asbeing “directly on” another element, there are no intervening elementspresent.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.Further, in the specification, the word “on” or “above” means disposedon or below the object portion, and does not necessarily mean disposedon the upper side of the object portion based on a gravitationaldirection.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “At least one” is not to be construed as limiting “a” or“an.” “Or” means “and/or.” As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising” will beunderstood to imply the inclusion of stated elements but not theexclusion of any other elements.

Further, throughout the specification, the phrase “on a plane” meansviewing a target portion from the top, and the phrase “on across-section” means viewing a cross-section formed by verticallycutting a target portion from the side.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10% or 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

To uniformly transmit a common voltage to a display device, contactresistance of a common voltage transmitting line is minimized. Forminimizing such contact resistance, a contact area between the commonvoltage transmitting line and the common electrode that are in contactwith each other is formed to be relatively large.

As a demand for a bezel-less display device of which a non-display areaaround a display area is not recognized outside the display device hasincreased. For this purpose, forming a relatively narrow width of theperiphery portion of the display area within the display device isdesired. However, by forming the contact area between the common voltagetransmitting line and the common electrode to be relatively large, itmay be difficult to minimize a width of the periphery portion of thedisplay area.

Now, a display device according to an exemplary embodiment will bedescribed with reference to FIG. 1 to FIG. 4. FIG. 1 is a top plan viewof an exemplary embodiment of a display device according to theinvention, FIG. 2 is a schematic cross-sectional view taken along lineII-II of FIG. 1, FIG. 3 is an equivalent circuit diagram of an exemplaryembodiment of a pixel of a display device according to the invention,and FIG. 4 is an enlarged cross-sectional view of an exemplaryembodiment of a contact area of the display device of FIG. 2.

Referring to FIG. 1, a display device 1000 according to one or moreexemplary embodiment includes a display area DA at which an image isdisplayed with light and a non-display area NDA disposed outside thedisplay area DA and at which the image is not displayed. The image mayalso be generated at the display area DA, by components of the displaydevice 1000 which are disposed therein.

The non-display area NDA includes a driving area PA in which a driver600 from and/or through which a signal is transmitted to the displayarea DA to drive the display area DA and displayed an image. The signalmay be an electrical signal such as a driving signal, a control signal,a power signal, etc.

In the non-display area NDA, a common voltage transmitting line 400through which a common voltage is transmitted and driving voltagetransmitting lines 500 a and 500 b through which a driving voltage istransmitted are disposed.

In the exemplary embodiment, the common voltage transmitting line 400starts from the driver 600 and encloses the display area DA along with aportion of the non-display area NDA. The driving voltage transmittinglines 500 a and 500 b include two portions separated from each other viathe display area DA. The arrangement of the common voltage transmittingline 400 and the driving voltage transmitting lines 500 a and 500 bshown in FIG. 1 is one example, and the invention is not limitedthereto.

The structure of the display area DA and the non-display area NDA willbe described with reference to FIG. 2 to FIG. 4.

Referring to FIG. 3, the display area DA of the display device 1000according to an exemplary embodiment includes a plurality of signallines 121, 171 and 172 and a pixel PX connected to the signal lines 121,171 and 172. The pixel PX may be provided in plurality and arranged inan approximate matrix. As used herein, the pixel PX means a minimum unitof displaying an image, and the display device 1000 displays an image byusing a plurality of pixels PX. The image may also be generated at thepixel PX by components of the display device 1000 therein.

The signal lines include a gate line 121 provided in plurality fortransmitting a gate signal (or a scan signal), a data line 171 providedin plurality for transmitting a data signal, and a driving voltage line172 provided in plurality for transmitting a driving voltage ELVDD. Thegate lines 121 are provided in a row direction and are substantiallyparallel with each other, such as having lengths thereof which aregreater than widths thereof and extend in a first direction (e.g.,horizontal in FIG. 3). The data lines 171 and the driving voltage lines172 are provided in a column direction and are substantially parallelwith each other such as having lengths thereof which are greater thanwidths thereof and extend in a second direction (e.g., vertical in FIG.3) crossing the first direction.

The display device 1000 and components thereof may be disposed in aplane defined by the first and second directions which cross each other(e.g., horizontal and vertical in FIG. 1 and FIG. 3). A thickness of thedisplay device and components thereof may extend along a third direction(e.g., vertical in FIG. 2 and FIG. 4) which crosses each of the firstand second directions.

Each pixel PX includes one or more switching element such as a thin filmtransistor. Referring to FIG. 3, each pixel PX includes a switching thinfilm transistor Qs, a driving thin film transistor Qd, a storagecapacitor Cst, and an organic light emitting diode (“OLED”) LD as anorganic light emitting element. Although not shown in the drawing, thepixel PX may further include another thin film transistor and anothercapacitor so as to compensate the electrical current supplied to theorganic light emitting element.

The switching thin film transistor Qs has a control terminal, an inputterminal and an output terminal. The control terminal of the switchingthin film transistor Qs is connected to the gate line 121, the inputterminal thereof is connected to the data line 171, and the outputterminal thereof is connected to the driving thin film transistor Qd.Where a data signal is applied to the data line 171, the switching thinfilm transistor Qs transmits the data signal applied from the data line171 to the driving thin film transistor Qd in response to the scanningsignal applied to the gate line 121.

The driving thin film transistor Qd also has a control terminal, aninput terminal and an output terminal. The control terminal of thedriving thin film transistor Qd is connected to the switching thin filmtransistor Qs, the input terminal thereof is connected to the drivingvoltage line 172, and the output terminal thereof connected to theorganic light emitting diode LD. The driving thin film transistor Qddifferentiates magnitudes of the flow of electrical output (electrical)currents ILD depending upon the voltages (e.g., a difference involtages) between the control and the output terminals thereof.

The storage capacitor Cst is connected between the control terminal andthe input terminal of the driving thin film transistor Qd. The storagecapacitor Cst is electrically charged with the data signals applied tothe control terminal of the driving thin film transistor Qd, and storessuch signals even after the switching thin film transistor Qs turns off.

The organic light emitting diode LD has an anode connected to the outputterminal of the driving thin film transistor Qd and a cathode connectedto a conductive line through and from which a common voltage ELVSS istransmitted. The organic light emitting diode LD changes intensity togenerate and emit light depending on the output current ILD of thedriving thin film transistor Qd to thus display the image with thelight.

Now, an interlayer structure of the display device 1000 will bedescribed with reference to FIG. 2.

As above-described, the display device 1000 includes the display area DAand the non-display area NDA. As shown in FIG. 2, the non-display areaNDA includes a contact area CA.

The display device 1000 includes a (base) substrate 100 on which layersof the display device 1000 are disposed. The substrate 100 may beflexible and include a first insulating film 100 a and a secondinsulating film 100 b overlapping each other. The first insulating film100 a and the second insulating film 100 b may each include polyimide.However, the first insulating film 100 a and the second insulating film100 b are not limited thereto, and may include other materials that haveheat resistance, chemical resistance and abrasion resistance, and arealso flexible.

The substrate 100 further includes a first barrier film 100 c disposedbetween the first insulating film 100 a and the second insulating film100 b. The first barrier film 100 c reduces or effectively preventsmoisture and gas from being inflowed from outside the display device1000 and through an area between the first insulating film 100 a and thesecond insulating film 100 b. Where the inflow of moisture and gas areminimized, deformation of the first insulating film 100 a and the secondinsulating film 100 b is reduced or effectively prevented.

As the substrate 100 includes the first insulating film 100 a and thesecond insulating film 100 b overlapping each other, even if damage isgenerated in the first insulating film 100 a that is in contact with theoutside, deterioration of the performance of the substrate 100 may bereduced or effectively prevented. In an exemplary embodiment ofmanufacturing a conventional display device, for example, a substrate100 including the layers of the display device formed thereon issupported on a supporting substrate (not shown). The damage may begenerated at an interface between the substrate 100 and the supportingsubstrate in a process of separating the substrate 100 of which themanufacturing process is completed from a supporting substratesupporting the substrate 100. However, in one or more exemplaryembodiment according to the invention, as the substrate 100 of thedisplay device 1000 includes the first insulating film 100 a and thesecond insulating film 100 b overlapping each other, even if the damageis generated at the first insulating film 100 a closer to the supportingsubstrate than the second insulating film 100 b, the second insulatingfilm 100 b remains without damage thereto, thereby increasing thereliability of the overall substrate 100.

A groove 10 is formed or defined in the substrate 100 at the contactarea CA of the non-display area NDA. The groove 10 may be formed ordefined in the second insulating film 100 b and may extend in athickness direction to at least a part of the first insulating film 100a. The groove 10 will be described in detail later.

A buffer layer 120 is disposed on the substrate 100. The buffer layer120 may include a single layer of an insulating material layer such as asilicon nitride (SiNx) and a silicon oxide (SiOx), or a multilayer ofinsulating materials in which a silicon nitride (SiNx) and a siliconoxide (SiOx) are deposited. The buffer layer 120 reduces or effectivelyprevents penetration of an unnecessary component such as an impurity ormoisture to components or layers of the display device which aredisposed on the buffer layer 120.

Although not shown, a second barrier film (not shown) may be disposedbetween the second insulating film 100 b and the buffer layer 120.

A first semiconductor layer 135 is disposed on the buffer layer 120 ofthe display area DA. The first semiconductor layer 135 may include apolysilicon or oxide semiconductor. In this case, the oxidesemiconductor may include an oxide based on titanium (Ti), hafnium (Hf),zirconium (Zr), aluminum (Al), tantalum (Ta), germanium (Ge), zinc (Zn),gallium (Ga), tin (Sn), or indium (In), or complex oxides thereof.

The first semiconductor layer 135 includes a first channel region 1355,and a first source region 1356 and a first drain region 1357 disposed atrespective sides of the first channel region 1355. The first channelregion 1355 of the first semiconductor layer 135 may be a region inwhich an impurity is not doped, and the first source region 1356 and thefirst drain region 1357 of the first semiconductor layer 135 may be aregion in which a conductive impurity is doped. Each of the regions maybe formed from a same semiconductor material layer to which doping isapplied at different levels.

Similarly, a second semiconductor layer 145 is disposed on the bufferlayer 120 of the non-display area NDA. The second semiconductor layer145 includes a second channel region 1455, and a second source region1456 and a second drain region 1457 disposed at respective sides of thesecond channel region 1455. Each of the regions may be formed from asame semiconductor material layer to which doping is applied atdifferent levels.

A gate insulating layer 140 is disposed on the first semiconductor layer135 and the second semiconductor layer 145. The gate insulating layer140 may be a single layer including tetraethyl orthosilicate (“TEOS”), asilicon oxide (SiOx), a silicon nitride (SiNx) or a silicon oxynitride(SiON), or a multilayer thereof.

A first gate electrode 155 and a second gate electrode 156 are disposedon the gate insulating layer 140. The first gate electrode 155 overlapsthe first channel region 1355, and the second gate electrode 156overlaps the second channel region 1455.

The first gate electrode 155 and the second gate electrode 156 may be asingle layer or a multilayer, including a relatively low (electrical)resistance material such as aluminum (Al), titanium (Ti), molybdenum(Mo), copper (Cu), nickel (Ni), or alloys thereof, or a material havinga relatively strong resistance against corrosion.

A first interlayer insulating layer 160 is disposed on the first gateelectrode 155 and the second gate electrode 156. The first interlayerinsulating layer 160 may be the single layer including tetraethylorthosilicate (“TEOS”), a silicon oxide (SiOx), a silicon nitride (SiNx)or a silicon oxynitride (SiON), or a multilayer thereof.

The first interlayer insulating layer 160 and the gate insulating layer140 have a first source contact hole 166 and a first drain contact hole167 overlapping the first source region 1356 and the first drain region1357, and a second source contact hole 168 and a second drain contacthole 169 overlapping the second source region 1456 and the second drainregion 1457.

A first source electrode 173 and a first drain electrode 175, and asecond source electrode 176 and a second drain electrode 177, aredisposed on the first interlayer insulating layer 160. Also, a commonvoltage transmitting line 400 is disposed on the first interlayerinsulating layer 160 of the contact area CA of the non-display area NDA.

The first source electrode 173 and the first drain electrode 175 areconnected to the first source region 1356 and the first drain region1357 of the first semiconductor layer 135 through the first sourcecontact hole 166 and the first drain contact hole 167, respectively.Similarly, the second source electrode 176 and the second drainelectrode 177 are connected to the second source region 1456 and thesecond drain region 1457 of the second semiconductor layer 145 throughthe second source contact hole 168 and the second drain contact hole169, respectively.

The first source electrode 173 and the first drain electrode 175, andthe second source electrode 176 and the second drain electrode 177, maybe the single layer or the multilayer, including a relatively low(electrical) resistance material such as aluminum (Al), titanium (Ti),molybdenum (Mo), copper (Cu), nickel (Ni), or alloys thereof, or amaterial having relatively strong corrosion resistance. In an exemplaryembodiment of manufacturing a display device, the common voltagetransmitting line 400 may be simultaneously formed with the first sourceelectrode 173, the first drain electrode 175, the second sourceelectrode 176 and the second drain electrode 177. That is, these layersmay be formed from a same material layer and/or in a same manufacturingprocess, such that these layers are disposed in a same layer of thedisplay device among layers disposed on the substrate 100.

The first semiconductor layer 135, the first gate electrode 155, thefirst source electrode 173 and the first drain electrode 175 of thedisplay area DA form a driving thin film transistor Qd of the pixel PXshown in FIG. 3. The second semiconductor layer 145, the second gateelectrode 156, the second source electrode 176 and the second drainelectrode 177 of the non-display area NDA form a thin film transistorincluded in a gate driver (not shown) disposed on the substrate 100 atthe non-display area NDA thereof.

In FIG. 2, one transistor is respectively shown in each of the displayarea DA and the non-display area NDA, however this is for convenience ofexplanation, and the invention is not limited thereto.

As above-described, the groove 10 is formed in the substrate 100disposed at the contact area CA of the non-display area NDA. Each of theplurality of insulating layers, the buffer layer 120, the gateinsulating layer 140 and the first interlayer insulating layer 160disposed on the substrate 100 has a recess portion C disposed or formedalong the groove 10 of the substrate 100. Similarly, the common voltagetransmitting line 400 disposed at the contact area CA also overlaps thegroove 10 of the substrate 100, and accordingly the common voltagetransmitting line 400 also has the recess portion C disposed or formedalong the groove 10 of the substrate 100. As the common voltagetransmitting line 400 has the recess portion C disposed or formed alongthe groove 10 of the substrate 100, a total surface area of the commonvoltage transmitting line 400 disposed at the contact area CA isincreased.

Referring to FIG. 1, the common voltage transmitting line 400collectively includes portions thereof lengthwise extending in extensiondirections. First portions of the common voltage transmitting line 400lengthwise extend along the first direction (e.g., horizontal in FIG. 1)while widthwise extending along the second direction (e.g., vertical inFIG. 1). Second portions of the common voltage transmitting line 400lengthwise extend in the second direction and widthwise extend in thefirst direction. That is, taking FIGS. 1 and 2 together, the groove 10along which the common voltage transmitting line 400 is extended, mayalso include first and second portions corresponding to those of thecommon voltage transmitting line 400. In an exemplary embodiment, thefirst and second portions of the common voltage transmitting line 400and of the groove 10 may be respectively connected to each other to forma single collective common voltage transmitting line 400 and a singlecollective groove 10 without being limited thereto.

A second interlayer insulating layer 180 is disposed or formed on thefirst source electrode 173, the first drain electrode 175, the secondsource electrode 176 and the second drain electrode 177. The secondinterlayer insulating layer 180 may be the single layer includingtetraethyl orthosilicate (“TEOS”), a silicon oxide (SiOx), a siliconnitride (SiNx), or a silicon oxynitride (SiON), or a multilayer thereoflike the first interlayer insulating layer 160.

The second interlayer insulating layer 180 has a contact hole 82overlapping the first drain electrode 175. A portion of the material ofthe second interlayer insulating layer 180 is removed at a regionoverlapping the common voltage transmitting line 400 such that most ofthe common voltage transmitting line 400 does not overlap the secondinterlayer insulating layer 180 such that only the edge portion of thecommon voltage transmitting line 400 may overlap the second interlayerinsulating layer 180. However, in another exemplary embodiment, theentire common voltage transmitting line 400 may not overlap the secondinterlayer insulating layer 180 such that an entire of the commonvoltage transmitting line 400 is exposed by the second interlayerinsulating layer 180.

A pixel electrode 710 is disposed on the second interlayer insulatinglayer 180. The pixel electrode 710 may be an anode of an organic lightemitting diode of FIG. 3. In the exemplary embodiment, the secondinterlayer insulating layer 180 is disposed between the pixel electrode710 and the first drain electrode 175. However, where the pixelelectrode 710 and the first drain electrode 175 are in a same layer aseach other so as be integrated with each other, the second interlayerinsulating layer 180 may be disposed on the same layer including boththe pixel electrode 710 and the first drain electrode 175.

A partition (layer) 190 is disposed or formed on the pixel electrode710. The partition 190 has an opening 195 overlapping the pixelelectrode 710. The partition 190 may include a polyacrylate resin, apolyimide resin, a silica-based inorganic material, etc.

An organic emission layer 720 is disposed or formed in the opening 195of the partition 190.

The organic emission layer 720 may include an emission layer and atleast one of a hole injection layer (“HIL”), a hole transporting layer(“HTL”), an electron transporting layer (“ETL”) and an electroninjection layer (“EIL”). In the case where the organic emission layer720 includes all these layers, the hole-injection layer is disposed onthe pixel electrode 710 which is an anode, and the hole transportinglayer, the emission layer, the electron transporting layer and theelectron injection layer may be sequentially laminated thereon.

A common electrode 730 is disposed on the partition 190 and the organicemission layer 720. The common electrode 730 becomes a cathode of theorganic light emitting diode. Accordingly, the pixel electrode 710, theorganic emission layer 720 and the common electrode 730 form an organiclight emitting diode 70.

The organic light emitting diode 70 may have any one structure of a topdisplay type, a bottom display type and a dual-sided display typeaccording to a direction in which the organic light emitting diode 70emits light.

In the case of the front display type, the pixel electrode 710 includesor is formed of a reflective layer and the common electrode 730 includesor is formed of a transflective or transmissive layer. In contrast, inthe case of the rear display type, the pixel electrode 710 includes oris formed of a transflective layer and the common electrode 730 includesor is formed of a reflective layer. In the case of the dual-sideddisplay type, the pixel electrode 710 and the common electrode 730include or are formed of a transparent layer or a transflective layer.

The reflective layer and the transflective layer described above mayinclude or be made of at least one metal of magnesium (Mg), silver (Ag),gold (Au), calcium (Ca), lithium (Li), chromium (Cr), and aluminum (Al),or alloys thereof. The reflective layer and the transflective layer aredetermined by the thicknesses thereof, and the transflective layer mayhave a thickness of less than about 200 nanometers (nm). As thethickness of the layer is decreased, transmittance of light isincreased, but when the thickness is relatively very small, theelectrical resistance is increased. The transparent layer includes or ismade of a material of indium tin oxide (“ITO”), indium zinc oxide(“IZO”), zinc oxide (“ZnO”), indium oxide (In2O3) or the like.

The common electrode 730 may be disposed on the entire surface of thesubstrate 100 including the display area DA and the non-display areaNDA, and is in contact with the common voltage transmitting line 400 onthe contact area CA of the non-display area NDA, thereby receiving thecommon voltage from the common voltage transmitting line 400.

As above-described, the substrate 100 has the groove 10 disposed at thecontact area CA of the non-display area NDA, and the common voltagetransmitting line 400 has the recess portion C extended along a profileof the groove 10 of the substrate 100. Similarly, the common electrode730 contacted with the common voltage transmitting line 400 also has arecess portion C disposed in the contact area CA. In this way, thecommon voltage transmitting line 400 and the common electrode 730 thatare in contact with each other in the contact area CA each have therecess portion C extended along the groove 10 formed in the substrate100 such that a total contact area between the common voltagetransmitting line 400 and the common electrode 730 is increased, therebydecreasing the contact resistance therebetween.

A planar area of an element of the display device may be defined by aproduct of two dimensions respectively taken in two directions whichcross each other. Referring to FIG. 1 and FIG. 2 and considering a planedefined by the first and second directions described above, a planararea of the contact area CA of the substrate 100 may be defined by aproduct of a minimum length of the common voltage transmitting line 400contacting the common electrode 730 and a minimum width of the commonvoltage transmitting line 400 contacting the common electrode 730.

Referring again to FIG. 1 and FIG. 2, an actual surface area of thecommon voltage transmitting line 400 contacting the common electrode 730includes not only planar dimensions of these features in the first andsecond directions, but also includes dimensions along the third(thickness) direction. That is, since an actual surface area of thecommon voltage transmitting line 400 includes the recess portions Cthereof disposed or formed along the groove 10 in a thickness directionof the substrate 100, a total actual surface area of the common voltagetransmitting line 400 contacting the common electrode 730 may be largerthan a total planar area of the contact area CA of the substrate 100 atwhich the common voltage transmitting line 400 contacts the commonelectrode 730. That is, the total contact area between the commonvoltage transmitting line 400 and the common electrode 730 is increasedto be larger than the planar area of the contact area CA, therebydecreasing the contact resistance between the common voltagetransmitting line 400 and the common electrode 730.

A spacer SP is located on an outer portion of the non-display area NDA.The spacer SP may be a multilayer element formed from portions ofmaterial layers disposed in the display area DA. In an exemplaryembodiment, the spacer SP may include a first insulating layer portionincluding or made of the same (material) layer as the second interlayerinsulating layer 180, a pixel definition layer (such as the partition190) and an additional insulating layer.

An encapsulation layer 80 is disposed on the common electrode 730. Theencapsulation layer 80 may be collectively formed by alternatelydepositing at least one inorganic layer and at least one organic layer.In an exemplary embodiment, a plurality of inorganic layers or aplurality of organic layers may be included in the encapsulation layer80.

In the exemplary embodiment, the encapsulation layer 80 includes a firstinorganic encapsulation layer 810 and a second inorganic encapsulationlayer 820, and further includes an organic encapsulation layer 830disposed between the first inorganic encapsulation layer 810 and thesecond inorganic encapsulation layer 820.

The first inorganic encapsulation layer 810 and the second inorganicencapsulation layer 820 are disposed or formed on the entire surface ofthe substrate 100 such that they are also disposed on the spacer SP. Theorganic encapsulation layer 830 is not disposed outside the spacer SPtoward an edge of the substrate 100 among portions of the non-displayarea NDA.

In an exemplary embodiment of manufacturing a display device, whenforming the organic encapsulation layer 830, the spacer SP serves as adam to reduce or effectively prevent an organic material for forming theorganic encapsulation layer 830 from overflowing. Since the organicmaterial does not overflow the spacer SP and is not disposed furtherthan the spacer SP, the organic encapsulation layer 830 may not beformed outside the spacer SP toward the edge of the substrate 100. Inthe exemplary embodiment, the substrate 100 has the groove 10 positionedat the contact area CA, and the organic material for forming the organicencapsulation layer 830 may be further efficiently reduced oreffectively prevented from overflowing through a relatively large stepformed by the recess portions C at the groove 10 near the spacer SP.

The structure of one pixel disposed in the display area DA of thedisplay device is shown in FIG. 2 and FIG. 3, but the pixel structure ofthe display device according to an exemplary embodiment of the inventionis not limited to the structure shown in FIG. 2 and FIG. 3. The signalline and the organic light emitting diode can be formed with variousstructures within a range which can be easily modified by technicalexperts. In an exemplary embodiment, for example, in FIG. 3, as thedisplay device, one in which one pixel includes two thin filmtransistors (TFTs) and one capacitor is shown, but the invention is notlimited thereto. Accordingly, the display device is not limited to thenumber of thin film transistors, the number of the capacitors and/or andthe number of the wires.

As shown in FIG. 2 and FIG. 4, the substrate 100 of the display deviceaccording to the exemplary embodiment has the groove 10 disposed at thecontact area CA of the non-display area NDA. The common voltagetransmitting line 400 and the common electrode 730 that are in contactwith each other at the contact area CA each has a recess portion Cextended along the groove 10 of the substrate 100. Accordingly, a totalcontact area between the common voltage transmitting line 400 and thecommon electrode 730 is increased by being extended along a thicknessdirection without extending the width of the contact area CA in a planardirection, and the contact resistance therebetween decreases owing tothe increased total contact area.

Referring to FIG. 4, the edge of the groove 10 of the substrate 100 isinclined with respect to the lower surface of the substrate 100 to forma first angle θ, and the groove 10 has a taper structure of which across-section gradually increases along a direction from the substrate100 toward the thin film encapsulation layer 80. That is, a side portionof the substrate 100 at the groove 10 forms the first angle θ with alower surface of the substrate 100. Accordingly, by the insulatinglayers extending along the first angle θ into the groove 10 in thethickness direction, the overlying common voltage transmitting line 400and the common electrode 730 also extend along the first angle θ in thethickness direction such that disconnection thereof at the groove 10 maybe reduced or effectively prevented.

The contact area CA of the display device according to another exemplaryembodiment will be described with reference to FIG. 5. FIG. 5 is across-sectional view of another exemplary embodiment of a contact areaof a display device according to the invention.

Referring to FIG. 5, the contact area CA of the display device accordingto the present exemplary embodiment is similar to the contact area CA ofthe display device according to the exemplary embodiment described withreference to FIG. 4. The detailed description for the same constituentelements will be omitted.

The substrate 100 of the display device according to one or moreexemplary embodiment has a first groove 10 a defined or formed in thefirst insulating film 100 a as well as the second insulating film 100 b.The first groove 10 a penetrates completely through the secondinsulating film 100 b of the substrate 100 and extends into the firstinsulating film 100 a. In this way, as the first groove 10 a extendsinto a portion the first insulating film 100 a, a total depth of thefirst groove 10 a increases. Accordingly, the depth of the recessportion C of the common voltage transmitting line 400 and the commonelectrode 730 extended along the first groove 10 a also deepens ascompared to where a groove does not extend into the first insulatingfilm 100 a and terminates at the first barrier layer 100 c. Therefore, atotal contact area of the common voltage transmitting line 400 and thecommon electrode 730 may become larger as the total depth of the grooveformed in the substrate 100 is increased.

Features of the display device according to the exemplary embodimentdescribed with reference to FIG. 1 to FIG. 4 are applicable to thedisplay device of FIG. 5.

The contact area CA of the display device according to still anotherexemplary embodiment will be described with reference to FIG. 6. FIG. 6is a cross-sectional view of still another exemplary embodiment of acontact area of a display device according to the invention.

Referring to FIG. 6, the contact area CA of the display device accordingto the exemplary embodiment is similar to the contact area CA of thedisplay device according to the exemplary embodiment described withreference to FIG. 4. The detailed description for the same constituentelements is omitted.

The substrate 100 of the display device according to the presentexemplary embodiment has the groove 10 provided in plurality disposed atthe contact area CA. In this way, as the substrate 100 has the pluralityof grooves 10, a total cross-section of the recess portion C taken alongthe grooves 10 increases. Accordingly, a total contact area of thecommon voltage transmitting line 400 and the common electrode 730 thatare in contact with each other in the contact area CA may furtherincrease as the number of grooves increases at the contact area CA.

Features of the display devices according to the exemplary embodimentdescribed with reference to FIG. 1 to FIG. 4 and the exemplaryembodiment described with reference to FIG. 5 are applicable to thedisplay device of FIG. 6.

The substrate 100 of the display device according to one or more of theabove-described exemplary embodiments has the groove 10/10 a disposed atthe contact area CA, and the common voltage transmitting line 400 andthe common electrode 730 that are in contact with each other at thecontact area CA have the recess portion C extended along the groove10/10 a of the substrate 100. Accordingly, the contact area between thecommon voltage transmitting line 400 and the common electrode 730 isincreased without increasing a planar width of the contact area CA, andthe contact resistance decreases therebetween.

A comparative example will now be described with reference to FIG. 7.FIG. 7 is a cross-sectional view of a contact area of a display deviceaccording to a comparative example.

Referring to FIG. 7, the substrate 10 does not have the groove alongwhich overlying layers extend to increase an area thereof. Accordinglythe common voltage transmitting line 400 and the common electrode 730disposed at the first contact area CA1 are extended substantially flatwithout the recess portion corresponding to the groove. Accordingly, thesurfaces of the common voltage transmitting line 400 and the commonelectrode 730 that are in contact with each other at the first contactarea CA1 are also substantially flat. Therefore, when the total contactarea of the common voltage transmitting line 400 and the commonelectrode 730 connected with each other at the first contact area CA1 isthe same as the total contact area of the common voltage transmittingline 400 and the common electrode 730 of the display devices accordingto the exemplary embodiments described with reference to FIG. 1 to FIG.6, a total planar width of the first contact area CA1 is greater than atotal planar width of the contact area CA of the display deviceaccording to the above-described exemplary embodiments.

Accordingly, while the width of the contact area CA of the displaydevice according to one or more of the above-described exemplaryembodiments is formed to be narrower than the width of the first contactarea CA1 of the display device according to the comparative example, inboth structures, the contact areas of the common voltage transmittingline 400 and the common electrode 730 may be maintained to be equal toeach other.

In an exemplary embodiment of manufacturing a display device, the groove10 of the substrate 100 disposed at the contact area CA of the displaydevice according to one or more of the exemplary embodiments may beformed by using a laser. The groove of the substrate 100 may be formedbefore depositing a plurality of insulating layers on the substrate 100,or may be formed after depositing a plurality of insulating layers onthe substrate 100.

Experimental examples will be described with reference to FIG. 8 andFIG. 9. FIG. 8 and FIG. 9 are electron micrographs showing exemplaryembodiments of a contact area of a display device according toexperimental examples.

The groove is formed in the substrate by using the laser in theexperimental example. FIG. 8 shows a case that the groove is only formedin the second insulating film 100 b disposed relatively higher among thefirst insulating film 100 a and the second insulating film 100 brelative to the substrate 100. FIG. 9 shows a case that the groove isalso formed at the portion of the first barrier film 100 c and the firstinsulating film 100 a each disposed under the second insulating film 100b as well as in the second insulating film 100 b of the substrate 100.

Referring to FIG. 8 and FIG. 9, it may be confirmed that the groove maybe formed in the substrate 100 by using the laser. Additionally, thegroove formed by using the laser in each of FIG. 8 and FIG. 9 may beformed to have the tapered structure without disconnection of theoverlaying layer thereof.

A display device according to another exemplary embodiment of theinvention will be described with reference to FIG. 10. FIG. 10 is aschematic cross-sectional view of another exemplary embodiment of adisplay device according to the invention.

Referring to FIG. 10, the display device according to the exemplaryembodiment shown in FIG. 10 is similar to the display device accordingto the exemplary embodiment shown in FIG. 2. The detailed descriptionfor the same constituent elements is omitted.

The display device according to the exemplary embodiment shown in FIG.10 further includes a touch portion 90 disposed on the thin filmencapsulation layer 80. The touch portion 90 includes a first touchelectrode 910 and a second touch electrode 920, and a touch insulatinglayer 930 disposed between the first touch electrode 910 and the secondtouch electrode 920. An input to the display device, such as contact ora touch from an external element, may be applied to the touch portion90.

The substrate 100 of the display device according to the presentexemplary embodiment has the groove 10 disposed at the contact area CA,and the common voltage transmitting line 400 overlapping the groove 10has the recess portion C disposed or formed along the groove 10.Accordingly, compared with the case that the common voltage transmittingline 400 does not have the recess portion C, an average interval betweenthe first touch electrode 910 and the second touch electrode 920disposed on the thin film encapsulation layer 80, and the common voltagetransmitting line 400, is relatively larger. As the average intervalbetween the first touch electrode 910 and the second touch electrode920, and the common voltage transmitting line 400, increases, couplingthat may be undesirably generated between the first touch electrode 910and the second touch electrode 920, and the common voltage transmittingline 400, may be reduced or effectively prevented.

Features of the display devices according to the exemplary embodimentdescribed with reference to FIG. 1 to FIG. 4, FIG. 5 and FIG. 6 areapplicable to the display device according to the exemplary embodimentshown in FIG. 10.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A display device comprising: a substrateincluding: a display area at which an image is displayed with light, anon-display area which is adjacent to the display area, and a groove inthe substrate, in the non-display area thereof; a light emitting elementwhich generates and emits the light, disposed on the substrate in thedisplay area thereof; and a common voltage transmitting line throughwhich a common voltage is transmitted to the display area, disposed onthe substrate in the non-display area thereof, wherein the substratefurther includes in each of the display area and non-display areathereof: a first insulating film, and a second insulating film disposedon the first insulating film, and the groove extends into the secondinsulating film in a direction toward the first insulating film.
 2. Thedisplay device of claim 1, wherein the common voltage transmitting lineoverlaps the groove in the substrate.
 3. The display device of claim 2,wherein the light emitting element includes an electrode layer throughwhich the common voltage is transmitted to the light emitting element,and the electrode layer of the light emitting element is in contact withthe common voltage transmitting line at a position overlapping thegroove.
 4. The display device of claim 3, wherein the groove in thesubstrate extends only into the second insulating film.
 5. The displaydevice of claim 3, wherein the substrate further includes a firstbarrier film disposed between the first insulating film and the secondinsulating film, and the groove in the substrate penetrates the secondinsulating film and extends into the first barrier film.
 6. The displaydevice of claim 3, wherein the groove in the substrate penetrates thesecond insulating film and extends into the first insulating film. 7.The display device of claim 3, wherein in the non-display area of thesubstrate, the groove is plural in the substrate, the common voltagetransmitting line overlaps each of the grooves in the substrate, and theelectrode layer of the light emitting element is in contact with thecommon voltage transmitting line at each of positions respectivelyoverlapping the grooves.
 8. The display device of claim 2, wherein thegroove in the substrate extends only into the second insulating film. 9.The display device of claim 2, wherein the substrate further includes afirst barrier film disposed between the first insulating film and thesecond insulating film, and the groove in the substrate penetrates thesecond insulating film and extends into the first barrier film.
 10. Thedisplay device of claim 2, wherein the groove in the substratepenetrates the second insulating film and extends into the firstinsulating film.
 11. The display device of claim 2, wherein in thenon-display area of the substrate, the groove is plural in thesubstrate, and the common voltage transmitting line overlaps each of thegrooves in the substrate.
 12. A display device comprising: a substrateincluding: a first insulating film, a second insulating film disposed onthe first insulating film, and a groove extended into the secondinsulating film in a direction toward the first insulating film; a pixelat which an image is displayed; and a common voltage transmitting linethrough which a common voltage is transmitted to the pixel, disposed onthe substrate, wherein the common voltage transmitting line overlaps thegroove in the substrate, and the common voltage transmitting line isconnected to the pixel at a position overlapping the groove.
 13. Thedisplay device of claim 12, wherein the groove in the substrate extendsonly into the second insulating film.
 14. The display device of claim12, wherein the substrate further includes a first barrier film disposedbetween the first insulating film and the second insulating film, andthe groove penetrates the second insulating film and extends into thefirst barrier film.
 15. The display device of claim 12, wherein thegroove in the substrate penetrates the second insulating film andextends into the first insulating film.
 16. The display device of claim12, wherein the groove is plural in the substrate, the common voltagetransmitting line overlaps each of the grooves in the substrate, and thecommon voltage transmitting line is connected to the pixel at each ofpositions respectively overlapping the grooves.
 17. The display deviceof claim 12, further comprising an insulating layer between thesubstrate and the common voltage transmitting line, wherein theinsulating layer extends into the groove in the substrate to have arecessed portion of the insulating layer corresponding to the groove,and the common voltage transmitting line extends into the recessedportion of the insulating layer, and at the recessed portion of theinsulating layer, the common voltage transmitting line is connected tothe pixel.
 18. The display device of claim 1, wherein the light emittingelement includes an electrode layer through which the common voltage istransmitted to the light emitting element, at the groove, the electrodelayer of the light emitting element is in contact with the commonvoltage transmitting line, a planar area of the substrate at which theelectrode layer of the light emitting element is in contact with thecommon voltage transmitting line defines a contact area of thesubstrate, and a total surface area of the electrode layer which is incontact with the common voltage transmitting line is larger than thecontact area of the substrate.
 19. The display device of claim 1,wherein the light emitting element includes an electrode layer throughwhich the common voltage is transmitted to the light emitting element,the common voltage transmitting line extends into the groove defined inthe substrate, in the non-display area thereof, and within the groove,the electrode layer of the light emitting element is in contact with thecommon voltage transmitting line.